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ITRM20070664A1 - AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS - Google Patents

AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS

Info

Publication number
ITRM20070664A1
ITRM20070664A1 IT000664A ITRM20070664A ITRM20070664A1 IT RM20070664 A1 ITRM20070664 A1 IT RM20070664A1 IT 000664 A IT000664 A IT 000664A IT RM20070664 A ITRM20070664 A IT RM20070664A IT RM20070664 A1 ITRM20070664 A1 IT RM20070664A1
Authority
IT
Italy
Prior art keywords
petrol
injectors
ammonia
power supply
diesel engines
Prior art date
Application number
IT000664A
Other languages
Italian (it)
Inventor
Luciano Cippittani
Original Assignee
Icomet Spa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Icomet Spa filed Critical Icomet Spa
Priority to IT000664A priority Critical patent/ITRM20070664A1/en
Priority to AU2008341434A priority patent/AU2008341434B2/en
Priority to US12/526,212 priority patent/US8146575B2/en
Priority to CA2709966A priority patent/CA2709966C/en
Priority to PCT/IT2008/000775 priority patent/WO2009081441A1/en
Priority to EP08865211A priority patent/EP2232043B1/en
Priority to CN2008801269056A priority patent/CN101946083B/en
Publication of ITRM20070664A1 publication Critical patent/ITRM20070664A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/023—Valves; Pressure or flow regulators in the fuel supply or return system
    • F02M21/0239—Pressure or flow regulators therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/021—Control of components of the fuel supply system
    • F02D19/023—Control of components of the fuel supply system to adjust the fuel mass or volume flow
    • F02D19/024—Control of components of the fuel supply system to adjust the fuel mass or volume flow by controlling fuel injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/026—Measuring or estimating parameters related to the fuel supply system
    • F02D19/027—Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0209—Hydrocarbon fuels, e.g. methane or acetylene
    • F02M21/0212—Hydrocarbon fuels, e.g. methane or acetylene comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0245—High pressure fuel supply systems; Rails; Pumps; Arrangement of valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0606—Fuel temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0618—Actual fuel injection timing or delay, e.g. determined from fuel pressure drop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/60—Input parameters for engine control said parameters being related to the driver demands or status
    • F02D2200/602—Pedal position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/31—Control of the fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
IT000664A 2007-12-20 2007-12-20 AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS ITRM20070664A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
IT000664A ITRM20070664A1 (en) 2007-12-20 2007-12-20 AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS
AU2008341434A AU2008341434B2 (en) 2007-12-20 2008-12-18 System for supply of LPG, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuel supplied to the injectors
US12/526,212 US8146575B2 (en) 2007-12-20 2008-12-18 System for supply of LPG, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuel supplied to the injectors
CA2709966A CA2709966C (en) 2007-12-20 2008-12-18 System for supply of lpg, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuelsupplied to the injectors
PCT/IT2008/000775 WO2009081441A1 (en) 2007-12-20 2008-12-18 System for supply of lpg, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuel supplied to the injectors
EP08865211A EP2232043B1 (en) 2007-12-20 2008-12-18 System for supply of lpg, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuel supplied to the injectors
CN2008801269056A CN101946083B (en) 2007-12-20 2008-12-18 System for supply of lpg, methane, ammonia, and gas in general for petrol or diesel engines with electronic pressure regulator for continuous variation of the pressure of the fuel supplied to the injectors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT000664A ITRM20070664A1 (en) 2007-12-20 2007-12-20 AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS

Publications (1)

Publication Number Publication Date
ITRM20070664A1 true ITRM20070664A1 (en) 2009-06-21

Family

ID=40315842

Family Applications (1)

Application Number Title Priority Date Filing Date
IT000664A ITRM20070664A1 (en) 2007-12-20 2007-12-20 AMMONIA AND GAS METHANE LPG POWER SUPPLY FOR PETROL OR DIESEL ENGINES WITH ELECTRONIC PRESSURE REGULATOR FOR THE CONTINUOUS CHANGE OF FUEL PRESSURE SUPPLIED TO INJECTORS

Country Status (7)

Country Link
US (1) US8146575B2 (en)
EP (1) EP2232043B1 (en)
CN (1) CN101946083B (en)
AU (1) AU2008341434B2 (en)
CA (1) CA2709966C (en)
IT (1) ITRM20070664A1 (en)
WO (1) WO2009081441A1 (en)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1393176B1 (en) 2009-02-27 2012-04-11 Icomet Spa DEVICE FOR THE ACCOMMODATION OF AN LPG PUMP IN A TANK SUITABLE FOR ALLOWING THE PUMP WITHOUT EMPTYING THE LPG TANK PRESENT IN HIS PREVIOUSLY
KR20110021573A (en) * 2009-08-26 2011-03-04 현대자동차주식회사 Fuel supplying system of lpi engine
DE102010020795A1 (en) * 2010-05-18 2011-01-13 Daimler Ag Pressure regulating arrangement for loading internal combustion engine of motor vehicle with e.g. liquefied petroleum gas, has heating device including latent heat accumulator and heating pressure regulator up to specific temperature
DE102010034227A1 (en) * 2010-08-07 2012-02-09 Daimler Ag Internal combustion engine, in particular for a motor vehicle
DE102010049713A1 (en) * 2010-10-26 2012-04-26 Borgwarner Beru Systems Gmbh Method for operating an evaporator for liquid gas and evaporator
US8919324B2 (en) 2010-12-08 2014-12-30 Robin B. Parsons Fuel rail for liquid injection of a two-phase fuel
NL2006992C2 (en) 2011-06-24 2013-01-02 Indopar B V Method of switching from a liquefied gas fuel to a liquid fuel being provided to a direct injection combustion engine, and direct injection bi-fuel system for such an engine.
PL2788215T3 (en) * 2011-12-07 2020-06-15 Agility Fuel Systems Llc Systems and methods for monitoring and controlling fuel systems
KR101349509B1 (en) * 2012-05-24 2014-01-09 현대자동차주식회사 LPI Fuel System and Return Fuel Minimum Method thereof
US10087896B1 (en) 2012-10-14 2018-10-02 Alberto Martin Perez Liquefied light hydrocarbon fuel system for hybrid vehicle and methods thereto
US9371784B2 (en) 2012-12-21 2016-06-21 Caterpillar Inc. Dual fuel system having a damper
CN103485936B (en) * 2013-10-18 2015-07-22 贵州大学 Gas supplying device of gas vehicle engine
US9896179B2 (en) * 2015-01-30 2018-02-20 Daewoo Shipbuilding & Marine Engineering Co., Ltd. System and method for controlling fuel supply to engine of ship
US9840992B2 (en) * 2015-03-06 2017-12-12 Elwha Llc Fuel injector system and method for making air-filled diesel droplets
WO2017100871A1 (en) * 2015-12-14 2017-06-22 Robert Bosch Limitada Process for detecting internal fuel leakage in a combustion engine, and engine control unit
DE102015226446B4 (en) * 2015-12-22 2017-08-31 Continental Automotive Gmbh Method for determining the composition of the fuel used to operate an internal combustion engine
US20170009696A1 (en) * 2016-09-26 2017-01-12 Caterpillar Inc. System for controlling pressure of fuel supplied to engine
DE102018200410A1 (en) * 2018-01-11 2019-07-11 Ford Global Technologies, Llc Device for lubricant dosing
CN113202638A (en) * 2021-05-27 2021-08-03 哈尔滨工程大学 Near-zero emission liquid ammonia-diesel dual-fuel supply system
CN113202637A (en) * 2021-05-27 2021-08-03 哈尔滨工程大学 Liquid ammonia-diesel oil dual-fuel injection device
CN113446134A (en) * 2021-06-16 2021-09-28 哈尔滨工程大学 Gaseous ammonia fuel supply system with stable injection pressure

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535728A (en) * 1984-02-02 1985-08-20 Propane Carburetion Systems, Inc. Fuel feed control system and control valve for dual fuel operation of an internal combustion engine
US4502453A (en) 1984-04-03 1985-03-05 General Motors Corporation Dual fuel supply system
JPH06502473A (en) 1990-11-20 1994-03-17 ジ　エナジー　リサーチ　アンド　ディベロプメント　コーポレイション Fuel injection method
WO1992008888A1 (en) 1990-11-20 1992-05-29 Biocom Pty. Ltd. A dual fuel injection system and a method of controlling such a system
US5450832A (en) * 1994-03-21 1995-09-19 Bruce R. Graf Dual fuel system
US6289881B1 (en) * 1997-08-28 2001-09-18 Alternative Fuel Systems Conversion system with electronic controller for utilization of gaseous fuels in spark ignition engines
US20020195086A1 (en) * 1997-12-16 2002-12-26 Beck N. John Cylinder pressure based optimization control for compression ignition engines
US6273076B1 (en) * 1997-12-16 2001-08-14 Servojet Products International Optimized lambda and compression temperature control for compression ignition engines
JP3883025B2 (en) * 1998-03-26 2007-02-21 ヤマハマリン株式会社 In-cylinder fuel injection engine
US6250260B1 (en) * 1998-10-13 2001-06-26 Jason E. Green Bi-fuel control system and assembly for reciprocating diesel engine powered electric generators
JP2003193874A (en) * 2001-12-26 2003-07-09 Nippon Ekosu Kk Dual fuel diesel engine combining gas fuel
US7607421B2 (en) * 2006-04-20 2009-10-27 Woodward Governor Company Pulsation-dampening fuel trim strategy for air/fuel ratio control of propane-fueled, spark-ignited engines

Also Published As

Publication number Publication date
AU2008341434A1 (en) 2009-07-02
US20100010727A1 (en) 2010-01-14
WO2009081441A1 (en) 2009-07-02
CA2709966C (en) 2016-04-12
EP2232043A1 (en) 2010-09-29
CA2709966A1 (en) 2009-07-02
CN101946083B (en) 2013-04-03
US8146575B2 (en) 2012-04-03
AU2008341434B2 (en) 2013-04-18
EP2232043B1 (en) 2013-02-13
CN101946083A (en) 2011-01-12

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